No other information is provided on it, other than the promise for a preview when it's ready.

Magister's Terrace was released in Patch 2.4 and contained higher-than-normal item level equipment and weapons for players. Many people felt that Magsiter's Terrace was also the hardest 5-man dungeon introduced into the game at the time.

While there is no indication that this dungeon will be released with patch 3.2, I don't think it's a wild assumption to make. Blizzard has previously indicated a future patch will also contain a new battleground.